Re-enterable splice enclosure

ABSTRACT

A re-enterable enclosure for a splice between cables, comprises two cover members with internal walls that are configured to form a cavity for enclosing the cable splice when the cover members are engaged with each other in a closed position. At least one of the cover members also has internal walls that are configured to define containment spaces which at least partly surround the cavity. In use, those containment spaces may contain sealant material. At least one internal wall in one cover member can telescope into a containment space in the other cover member so that, if sealant material is contained therein, it will be compressed when the cover members are engaged with each other in the closed position. By changing the containment spaces that are used to contain sealant material, different levels of protection against humidity can be provided for the cable splice in the cavity.

CROSS REFERENCE OF RELATED APPLICATION

The present invention is related to U.S. patent application Ser. No.10/770,095, titled MICROSPHERE-FILLED SEALANT MATERIALS, filed even dateherewith.

FIELD

The present invention relates to an enclosure for a splice betweencables, the enclosure being of the type that can be re-opened,re-enterable, to permit access to the cable splice when required and,preferably, then re-sealed. The cable may, for example, be atelecommunications cable, a power cable or an optical fibre cable.

The cable splice may, for example, be a longitudinally-extending splice(i.e. a splice between cables that extend generally from oppositedirections) or a so-called “pig-tail”, or butt, splice (i.e. a splicebetween cables that extend generally from the same direction).

BACKGROUND

A cable splice will generally require protection from the effects of theenvironment in which it is located and, more especially, will requireprotection against mechanical impact and the entry of moisture.Protection of the cables against strain will often also be required.Many different enclosures providing different levels of protection forcable splices are already available, including so-called re-enterableenclosures that can be re-opened to permit access to the splice wheneverrequired.

Known re-enterable splice enclosures often take the form of a two-partre-openable housing that defines a cavity around the splice and containsa sealant material. The housing provides protection for the spliceagainst mechanical impact and, in combination with the sealant material,protects the cavity to a required level against the entry of moisturewhile permitting access to the splice when the housing is re-opened. Insome cases, the cavity is completely filled with sealant material (see,for example, the splice enclosures described in U.S. Pat. No. 6,169,250and, in other cases, the sealant material is pre-formed by molding toparticular shapes for use in cable bushings that are located at the endsof the housing (see, for example, the splice enclosures described in WO02/063736).

SUMMARY

The present invention is concerned with providing a re-enterable spliceenclosure that is capable of providing adequate protection for a cablesplice against mechanical impact and the entry of moisture withoutrequiring the cavity surrounding the splice to be filled with anysuitable sealant material, and without requiring the sealant material tobe pre-formed to comparatively complex shapes for use in cable bushings.The invention is, accordingly, also concerned with providing are-enterable splice enclosure that is capable of providing adequateprotection for a cable splice against mechanical impact and the entry ofmoisture while using a comparatively small amount of sealant materialand while being comparatively simple to assemble.

The present invention provides a re-enterable enclosure for a splicebetween cables, the enclosure comprising two cover members with internalwalls that are configured to form a cavity for enclosing the cablesplice when the cover members are engaged with each other in a closedposition, wherein:

-   -   (i) at least one of the cover members has internal walls that        are configured to define containment spaces, suitable for        containing sealant material, that at least partly surround the        cavity, and    -   (ii) at least one internal wall in one cover member can        telescope into a containment space in the other cover member,        thereby to compress any sealant material contained therein, when        the cover members are engaged with each other in the closed        position.

Advantageously, at least one of the cover members comprisesstrain-relief members associated with cable entry paths into the cavity.The enclosure is then capable of providing the splice with protectionagainst the effects of cable strain in addition to that provided, by thecover members, against mechanical impact and that provided, by the covermembers in combination with any sealant material in the containmentspaces, against the entry of moisture.

BRIEF DESCRIPTION OF THE DRAWINGS

By way of example only, splice enclosures in accordance with theinvention will be described with reference to the accompanying drawingsin which:

FIG. 1 is a perspective view of an exemplary splice enclosure in an opencondition, showing the inside of the cover members;

FIG. 2 is an end view of the splice enclosure of FIG. 1 in the directionof the arrow II;

FIG. 3 is an enlarged view of one end of one of the cover members ofFIG. 1;

FIG. 4 is similar to FIG. 1 but shows another exemplary splice enclosurewith sealant material contained in the cover members;

FIG. 5 shows a longitudinal cross-section taken along line 5—5 of thesplice enclosure of FIG. 4 in a closed condition;

FIG. 6 shows the splice enclosure of FIG. 4 in an open condition andready to be closed around a cable splice;

FIG. 7 is similar to FIG. 1 and shows sealant material contained in thecover members;

FIG. 8 is a cross-sectional view of the splice enclosure of FIG. 7 inthe direction of the arrow 8—8;

FIG. 9 is an end view on an enlarged scale of part of a spliceenclosure, illustrating a modified hinge; and

FIG. 10 is a perspective view of yet another splice enclosure in an opencondition, showing the inside of the cover members.

DETAILED DESCRIPTION

FIG. 1 shows two elongate cover members 1, 3 that are used, in a mannerto be described below, to form a cylindrical protective enclosure for alongitudinal cable splice (not shown). The cover members 1, 3 are moldedcomponents formed from a suitable plastics material, for examplepolypropylene or polyamide, and are joined together along their innerlongitudinal edges 2 by a hinge 5. As illustrated, the hinge 5 isintegrally-molded with the cover members 1, 3 and comprises a region ofreduced thickness that defines the bending axis of the hinge. This typeof hinge is well known and is often referred to as a “living” hinge.

The cover members 1, 3 both include internal walls (described in greaterdetail below) that define central cavity regions 7, 9 respectively. Whenthe cover members 1, 3 are folded together about the hinge 5 and broughtinto engagement with each other to close the splice enclosure, thecavity regions 7, 9 together form a central enclosed cavity forcontaining the cable splice that is to be protected. To hold the covermembers 1, 3 together in the closed position, latching tabs 11 projectupwards from inside the outer longitudinal edge 10 of the upper covermember 1 so that they will slide into a latching space 10A behind theouter longitudinal edge 10 of the lower cover member 3 and engage inrespective recesses 12. In addition, to reduce the possibility of anyrelative movement between the cover members 1, 3 once they are in theclosed position, the lower cover member 3 is provided with pins 13 thatengage in apertures 14 in the upper cover member 1. In that way, thestress placed on the hinge 5 when the splice enclosure is in use islimited and the risk that the latching tabs 11 will inadvertentlydisengage from the openings 12 is minimized.

The cavity region 7 in the upper cover member 1 is defined between sidewalls 15 and double end walls 17 that stand up from the internal surfaceof the cover member. The side walls 15 are located slightly inside theinner and outer longitudinal edges 2, 10 of the cover member, and extendparallel thereto. The double end walls 17 extend between the ends of theside walls 15 and are arranged at a distance from the respective ends 19of the cover member 1, thereby creating a space 20 at each end of theupper cover member: each of those spaces 20 is intended, when the spliceenclosure is in use, to accommodate a respective upstanding cablestrain-relief structure 21 formed at the corresponding end of the lowercover member 3. The strain-relief structures 21 will be described below.The space 17A between the two walls of each double end wall 17 providesa containment space for sealant material, also described below.

The cavity region 9 in the lower cover member 3 is defined between sidewalls 22 and end walls 23 that stand up from the internal surface of thecover member. The side walls 22 are located slightly inside the innerlongitudinal edge 2 of the cover member and the inner wall 10B of thelatching space 10A, and extend parallel thereto. The end walls 23 extendbetween the ends of the side walls 22 and each is arranged at a distancefrom the respective strain-relief structure 21. The spaces that are thusformed around the cavity region 9, on the outside of the side and endwalls 22, 23, provide containment spaces for sealant material as will bedescribed below.

The side walls 15 and the double end wall 17 of the cavity region 7 inthe upper cover member 1 stand up above the level of the outer edge ofthe cover member and are positioned so that, when the cover members 1, 3are folded together into the closed position, the walls 15, 17 willtelescope into the containment space around the cavity region 9 in thelower cover member 3.

The cable entry paths into the splice enclosure are further defined bysemi-circular recesses 25B in the end walls of the cover member 1 andthe end wall 17 of the cavity region 7.

Referring now to FIG. 3, which is an enlarged view of one end of thelower cover member 3, it can be seen that each strain-relief structure21 comprises three spaced walls 25, arranged parallel to the adjacentend 19 of the lower cover member 3. The walls 25 contain cable openings25A that are offset relative to each other to define a convoluted cableentry path into the splice enclosure. The cable entry paths into thesplice enclosure are further defined by semi-circular recesses 25B inthe end walls of the cover member 3 and the end wall 23 of the cavityregion 9. Associated with the recess 25B in the end walls 23 areoptional surfaces 26 for guiding a cable into the cavity region 9 andproviding additional strain relief, if required.

The splice enclosure comprising the cover members 1, 3 can be usedwithout the addition of any sealant material (i.e. in the form shown inFIG. 1 and FIG. 3) to provide a basic level of protection againsthumidity for a longitudinal splice between two cables, in addition toprotection against mechanical impact and cable strain. The cable spliceis first prepared, and the cables are then placed on the lower covermember 3 with the splice itself positioned in the cavity region 9 andthe cables extending out of opposite ends of the cover member along thepaths defined by the openings 25A in the strain relief structures 21,and the recesses 25B in the walls 19, 17 and 23. The upper cover member1 is then folded down onto the lower cover member 3, around the hinge 5,and latched in the closed position. The cable splice is now protectedagainst mechanical impact and, to a basic level, against humidity by thecover members 1, 3 but is nevertheless readily accessible simply byunlatching the upper cover member and moving it to the open position.The convoluted cable paths defined by the openings 25A provide strainrelief for the cables, and ensure the integrity of the splice.

Referring to FIG. 4, if the cable splice requires a higher level ofprotection against humidity, sealant material 27 is provided in thecontainment spaces at the ends of the cavity regions 7, 9. To ensure, inthe case of the cavity region 9, that the sealant material 27 isretained within the containment spaces at the ends of the cavity (anddoes not enter the containment spaces at the sides), the walls 23 oflower cover member 3 are extended outwards at each end to providebarriers 23A. As a consequence, recesses 15A are cut in the tops of thewalls 15 of the upper cover member 1 to accommodate the tops of thebarriers 23A when the splice enclosure is closed.

The cable splice is then prepared and the cables are placed on the lowercover member 3 as described above and as illustrated in FIG. 6, whichshows the enclosure of FIG. 4 in the process of being used to protect alongitudinal splice between two cables 28. The cables are shown ascomprising two pairs of wires 28A (although that is not essential) andthey are positioned on the lower cover member 3 so that the connections28B between the individual wires 28A of one cable and those of the othercable are located within the cavity region 9 with the cables 28extending from opposite ends thereof, along the paths defined by theopenings 25A in the strain relief structures 21, and the recesses 25B inthe walls 19, and 23. The splice enclosure is then closed as describedabove, whereupon the tops of the barriers 23A in the lower cover member3 locate in the respective recesses 15A in the upper cover member 1. Atthe same time, the double walls 17 at the ends of the cavity region 7(with the sealant material 27 between them) will telescope into thesealant material 27 at the ends of the cavity region 9 as illustrated inFIG. 5, which shows a central longitudinal cross-section of the spliceenclosure from which the cables have been omitted for clarity. As aresult, the sealant material 27 at both ends of the inner cavity of thesplice enclosure is compressed and brought into effective sealingcontact with the cables and the adjacent surfaces of the cover members.Depending on its nature, the sealant material may also tend to flow outof the containment spaces and along the outside of the cables to alimited extent, thereby enhancing the sealing effect. The cable spliceis now protected to a higher level against humidity and, as before,against mechanical impact and cable strain but is still readilyaccessible simply by unlatching the upper cover member and moving it tothe open position.

The sealant material 27 for the enclosure of FIG. 4 may be provided inthe form of pre-shaped pieces of gel that are located in the containmentspaces at the ends of the cavity regions 7, 9. Alternatively, thesealant material may be provided in liquid form, in which case it ispoured into the containment spaces and cured there to a gel-likeconsistency before use. Any tendency for the liquid sealant material tooverflow from the containment spaces through the adjacent recesses 25A,25B can be limited by using a high viscosity sealant material with ashort curing time.

Referring to FIG. 7, if the cable splice requires an even higher levelof protection against humidity, additional sealant material 29 is alsoprovided in the containment spaces along the sides of the cavity region9 before the spliced cables are placed on the lower cover member 3 asdescribed above. In this case, the barrier 23A and associated recesses15A of FIG. 4 are not required and can be omitted. The splice enclosureis then closed as described above, whereupon the side walls 15 of thecavity region 7 as well as the double end walls 17 (with the sealantmaterial 27 between them) will telescope into the sealant material 29,27 at, respectively, the sides and the ends of the cavity region 9 asillustrated in the cross-sectional views of FIGS. 5 and 8. As a result,the inner cavity of the splice enclosure is surrounded by compressedsealant material and the cable splice is protected to an even higherlevel against humidity (and, as before, against mechanical impact andcable strain) but is still readily accessible simply by unlatching theupper cover member and moving it to the open position.

As described above, the sealant material 27, 29 for the enclosure ofFIG. 7 may be provided in the form of pre-shaped pieces of gel that arelocated in the containment spaces at the ends of the cavity region 7,and at the ends and sides of the cavity region 9. Alternatively, thesealant material may be provided in liquid form, in which case it ispoured into the containment spaces and cured there to a gel-likeconsistency before use.

A particular advantage of the splice enclosures comprising cover members1, 3 as described above is that one type of enclosure can be used toprovide several levels of protection against humidity simply by theinclusion of sealant material at appropriate locations within the covermembers. Indeed, the splice enclosure illustrated in FIG. 4 can be usedto provide the three different levels of protection illustrated in FIGS.1, 4 and 7 despite the fact that the barriers 23A are not required inevery case. For each level of humidity protection, effective protectionfor the splice against mechanical impact and cable strain is alsoprovided.

The splice enclosures are of simple construction, and use comparativelyfew components so that they are easy to assemble in the field, even atdifficult or inaccessible locations.

The modification required to change the level of protection (i.e. theaddition of sealant material) can be easily carried out by themanufacturer or installer, particularly when a liquid sealant materialis used because there is then no need to stock pieces of gel that arepreformed to a particular shape. The maximum amount of sealant material(FIG. 7) need be used only when absolutely necessary and is still lessthan that used in, for example, re-enterable splice enclosures in whichthe whole of the splice cavity is filled with sealant material.Consequently, the costs of splice enclosures comprising cover members 1,3 as described above can be lower than those in which the whole of thesplice cavity is filled with sealant material. In addition, the factthat the cavity regions 7, 9 are empty allows a greater number ofsplices to be accommodated within a single enclosure; provides betterenvironmental conditions in which to locate the splice(s) long-term; andsimplifies access to the splice(s) in the event of the enclosure beingre-opened.

Because only one sealant material is used in the splice enclosures shownin FIGS. 4 and 7 of the drawings, there are no sealing problemsassociated with interfaces between different sealing materials (forexample, at the junction of the sealant materials 27, 29 in FIG. 7 or atthe junction between the sealant materials 27 in the upper and lowercover members 1, 3). Moreover, the particular construction of the spliceenclosure (which, as described, causes the double end walls 17 in theupper cover member 1, and the sealant material 27 contained therein, totelescope into the sealant material 27 in the lower cover member 3 whenthe enclosure is closed) ensures that the cables 28 are entirelysurrounded by the sealant material 27 in the region immediately outsidethe central cavity 7, 9 of the enclosure. The possibility of air gapsaround the cables at these locations, which could occur if the sealantmaterial 27 in the upper cover member 1 were simply in face-to-facecontact with the sealant material 27 in the lower cover member andwhich, if present, could allow moisture to enter the central cavity 7,9, is thus eliminated.

Preferably, the sealant material 27, 29 has sufficient long-termresilience to ensure, once it has been compressed by closing the covermembers 1, 3, that effective sealing is maintained until the spliceenclosure is re-opened. Advantageously, the sealant material permits thesplice enclosure then to be re-sealed (and, if required, opened andre-sealed again several times) and to continue to provide the same levelof protection for the cable splice. A suitable sealant material isdescribed in our co-pending patent application Ser. No. 10/770,095 ofeven date entitled “MICROSPHERE-FILLED SEALANT MATERIALS”, and which isincorporated herein by reference. If required, however, one or moreexternal resilient members can be positioned in known manner at suitablelocations in the cover members 1, 3 to apply the required compressiveforce to the sealant material when the splice enclosure is closed.

It will be appreciated that various modifications could be made to theconstruction of the cover members 1, 3 without affecting the protectivefunction of the splice enclosure. In one modification, the single hinge5 between the two cover members 1, 3 is replaced by two hinges 5A, 5B asillustrated in FIG. 9. That modification enables the splice enclosure tobe closed by moving each cover member through only 90° relative to theadjacent hinge, thereby reducing the strain placed on each hinge. When asingle hinge 5 is employed, as shown in FIG. 2, it is not essential forthe hinge to be integrally-molded with the cover members; as analternative it could be a separate component in the form, for example,of a film or a tape that is insert molded or attached by adhesive. It isalso possible to modify the form, location and number of the latches 11,12 that are used to hold the cover members together in the closedposition.

The provision of the strain-relief structures 21 in the spliceenclosure, although convenient, will limit the size of cable with whichthe splice enclosure can be used. For use with larger-diameter cables,the strain-relief structures 21 can be omitted and conventional cableties used instead. Alternatively, the strain-relief structures 21 can bedesigned to accommodate the largest-diameter cables with which thesplice enclosure is intended to be used, and some additional mechanismcan be provided to enable the enclosure to be used with smaller-diametercables. FIG. 10, for example, shows a splice enclosure in which each ofthe strain-relief structures 21 is designed to accommodate a five-paircable, and the cover member 3 is extended at each end to providecompartments 30 in which smaller diameter cables (for example, two-paircables) can be secured using conventional cable ties. For that purpose,each compartment 30 is provided with a seat 32 that is aligned with thecable opening 25A of the adjacent strain-relief structure 21 andprovides support for a cable that enters the splice enclosure. If thecable is too small to be secured adequately by the strain-reliefstructure 21, it can be secured to the seat 32 by a cable tie (notshown) that is passed around the cable and the seat through an aperture34 in the cover member 3.

With the benefit of the teachings of this patent, one of skill in theart could apply the present invention to any size cable or any desiredpair count.

In the splice enclosure shown in FIG. 10, the cover member 1 is alsoextended at each end to the same extent as the cover member 3 so thatthe compartments 30 containing the seats 32 will be closed when thecover members 1, 3 are closed around a cable splice. In a modifiedversion, the cable seats 32 can simply be provided as extensions of thecover member and remain exposed when the splice enclosure is closed.

FIG. 10 also shows a further modification of the splice enclosure, inthe form of two areas of weakness 36 in the cover member 3 (one withineach of the compartments 30) that can be pierced by screws to enable theenclosure to be secured to a flat surface if required. As a furtheralternative, locations for screws can be provided in extensions of thecover member 3 so that they remain exposed and accessible when thesplice enclosure is closed.

FIG. 10 further illustrates that the cable openings/recesses 25A, 25B inthe walls of the containment spaces at the ends of the cavity regions 7,9 are all closed by breakable wall portions 26 prior to use of thesplice enclosure. Those wall portions 26 allow liquid sealant materialto be poured into the containment spaces up to the level of the top ofthe walls and retained during curing. Thereafter, because the wallportions 26 are breakable, they will be removed by the action of puttinga cable in place in the associated openings/recesses 25A, 25B therebyenabling the cable to be effectively embedded in the sealant material.Similar breakable wall portions could be employed in any of the othersplice enclosures described above with reference to the drawings.

FIG. 10 also shows the provision of a raised continuation 40 adjacentthe hinge 5 on the middle wall 25 of each of the strain-reliefstructures 21. Each of the raised continuations 40 is engageable in arespective aperture 41 on the other side of the hinge in the covermember 1, to provide additional protection for the hinge when the covermembers 1, 3 are closed.

It will further be appreciated that a splice enclosure of the samegeneral type as those illustrated in the drawings could be used toprotect a so-called “pig tail”, or butt, splice (i.e. a splice betweencables that extend generally from the same direction, rather than fromopposite directions as shown in FIG. 6). In that case, the spliceenclosure (including the strain-relief structures 21) would requiremodification to permit the cables to enter the enclosure generally fromthe same direction, rather than from opposite directions as illustratedin the drawings.

Further modification of the cable entry paths of any of the spliceenclosures described above with reference to the drawings would enableprotection to be provided for splices between different numbers ofcables, for example a longitudinal splice between one cable extendingfrom one direction and two cables extending from the other direction.

1. A re-enterable enclosure for a splice between cables, the enclosurecomprising: first and second cover members releasably engageable witheach other, wherein the cover members are joined to each other by atleast one hinge, the first and second cover members being configured toform a cavity for enclosing the cable splice when the cover members areengaged with each other in a closed position, wherein the cavity forenclosing the cable splice is essentially free of sealant material, andincluding: (i) a plurality of internal walls in the first cover memberconfigured to define a first containment space for containing sealantmaterial, wherein the first containment space at least partly surroundsthe cavity, and (ii) a plurality of internal walls in the second covermember, at least one of the plurality of internal walls configured totelescope into the first containment space in the first cover memberwhen the cover members are engaged with each other in the closedposition.
 2. A splice enclosure as claimed in claim 1, furthercomprising a cable entry path into the cavity, and wherein said cableentry path traverses the first containment space.
 3. A splice enclosureas claimed in claim 2, wherein the plurality of internal walls in thesecond cover member define a second containment space for containingsealant material.
 4. A splice enclosure as claimed in claim 2, whereinat least one of the first and second cover members further comprisesstrain-relief members associated with said cable entry path.
 5. A spliceenclosure as claimed in claim 1, wherein the plurality of internal wallsin the second cover member define a second containment space forcontaining sealant material, wherein the first and second containmentspaces are configured such that the containment space in one of thefirst and second cover members can telescope into the containment spacein the other one of the first and second cover members when the firstand second cover members are engaged with each other in the closedposition.
 6. A splice enclosure as claimed in claim 5, furthercomprising a sealant material contained in the first and secondcontainment spaces.
 7. A splice enclosure as claimed in claim 6, whereinthe first and second containment spaces all contain the same sealantmaterial.
 8. A splice enclosure as claimed in claim 1, furthercomprising a sealant material contained in the first containment space.9. A splice enclosure as claimed in claim 8, wherein the firstcontainment space contains a sealant material that has been poured intothe first containment space and then cured.
 10. A splice enclosure asclaimed in claim 1, wherein the splice cavity is of elongate form, andthe splice enclosure further comprises first and second cable entrypaths into the cavity from opposed ends thereof.
 11. A splice enclosureas claimed in claim 10, wherein the plurality of internal walls in atleast one of the first and second cover members are configured to definetransverse containment spaces at said opposed ends of the cavity, saidtransverse containment spaces oriented transverse to the elongate splicecavity.
 12. A splice enclosure as claimed in claim 11, wherein the cableentry paths traverse said transverse containment spaces.
 13. A spliceenclosure as claimed in claim 12, wherein the transverse containmentspaces are defined by the plurality of internal walls in both the firstand second cover members.
 14. A splice enclosure as claimed in claim 13,wherein the plurality of internal walls defining transverse containmentspaces in one of the first and second cover members can telescope intotransverse containment spaces in the other one of the first and secondcover member when the cover members are engaged with each other in theclosed position.
 15. A splice enclosure as claimed in claim 11, whereinthe plurality of internal walls in one of the first and second covermembers are configured to provide longitudinal containment spaces thatextend along both sides of the cavity between the opposed ends thereof.16. A splice enclosure as claimed in claim 15, wherein the plurality ofinternal walls in the other one of the first and second cover memberscan telescope into the longitudinal containment spaces when the covermembers are engaged with each other in the closed position.
 17. A spliceenclosure as claimed in claim 15, wherein none of the containment spacesare essentially free of sealant material.
 18. A splice enclosure asclaimed in claim 15, wherein the transverse containment spaces containsealant material.
 19. A splice enclosure as claimed in claim 18, whereinthe longitudinal containment spaces contain sealant material.
 20. Asplice enclosure as claimed in claim 1, wherein the cover members aremolded components.